So my car has been down a year now, it is no longer my daily driver (obviously), and I DO plan on rebuilding as a 427 Dart LT1 after they become available. However, I just bought a house, and I feel as though it may be a while before I get everything I need/want to do a proper engine build. SO, I was thinking in the mean time of getting a lower mileage used LT1 to put in to get it back on the road and enjoy the car again, allowing me to build up a 427 at my own pace and not feel the rush to get the car going again and cut corners on the build.

If I put in a used LT1, I figure I might as well put in a custom cam before putting the engine in the car, keeping revs under 6500 to keep the motor alive. I will NOT be doing a rebuild, as this will be a budget motor to get the car back on the road, and have some fun enjoying the car again. Other than a cam, rockers, springs, etc., I will also be installing my Canton RR pan and Melling 10% HV pump with GM 'white' HP oil spring for added bearing insurance, might also put in Impala head gasket, and mill stock heads to bump up compression some as well, since I will be running strictly E85, and have a wideband for tuning to optimal A/F ratio. My questions are as follows:

1) Should I replace the cam bearings (all or just front?) before putting it in, or should I just swap the cam out? b) If so, can this be done relatively inexpensively? Again, cost is a factor, and am not doing an engine rebuild.

2) What RPM's should I try to keep the car under to keep it living on the stock short block with a new cam, under 6500?

3) What tests should/can I do to the engine before putting it in the car? Leak down, compression, oil pressure, etc? If the engine is in need of a rebuild, I do not want to use it.

4) What would be a ballpark RWHP for a stock bottom end, cam-only, stock head, M6, peaking <6500 RPM, on gasoline? Is 350 rwhp possible? (I know I will be running higher CR and E85 which will add a few hp, but I just want to get a ballpark based on other's cam-only builds). On my old stock 170k mile engine, I dynoed 322/338 on stock cam with E85, boltons, maxxed out injectors, and mild ported heads (less than LE1 porting).

5) Any other suggestions?

I just want to get my car back on the road and enjoy it again, cruising, autox, local test/tune drag, instead of just letting it sit for another 2 years until I can build my "big" engine. It doesn't have to be "daily driver" reliable, but I also don't want the engine to go out or spin a bearing within a few months (or less) of me installing it either. Sorry for the long post, I just wanted to get some good advice on this. Thanks!

 

1) I'd swap cam bearings, cheap insurance I don't think the machine shop charged me much to do it, or you can always buy the tool and learn how yourself.
2) I'd say 6200~rpm give or take is a nice cut off
3) pretty much what you said
4) I've seen stock compression 93 octane cam only guys make 350-360rwhp through T56s quite often with cc306, gm847, similar sized cams.

my advice would just be to get in touch with a custom grinder like Lloyd Elliot to take the full advantage of the E85

 

2 more questions.
Can the cam bearings be replaced without tearing down the whole bottom end?

How far can the stock heads be milled down for max compression (running E85), and would anything be gained from going larger on the valves and valve job while the heads are off for milling? I would be happy with even 15rwhp from the higher CR and valves alone if possible.

Again this is a budget build stock bottom end build (w/cam)

 

larger valves on a stock bore can actually lead to power loss according to some due to valve shrouding.

nothing with a nice milling on the heads with an impala gasket to pick up some compression, not sure what the max is though.

I really don't know on the cam bearings honestly

 

With the items you've already mentioned (cam, RR's, milling etc.) plus the cost of the engine, you're already into this for over a grand unless you've got some of it onhand. I'd seriously consider fresh, stock rings and bearings just for the peace of mind, assuming that all the measurements will allow it. If not, then it's probably not the engine to use anyway.

 

Well I figured that I would be in for about a grand total, especially considering about $350 for a custom cam, but I do want to keep the costs as low as possible while still having a somewhat reliable engine. I know after a cam swap a lot of people spin bearings, and I was wanting mainly to prevent that from happening, so would the high pressure oil pump spring, in new 10%HV Melling pump and Canton RR pan (which I already have both) along with new cam bearings and RPM under 6500 be enough to prevent spinning bearings after a cam, or would I have to replace main and rod bearings too to prevent that?

 

Assuming that the donor engine has good oil pressure to begin with, it should be ok. I think you'll find that the bearings get spun due to the increased rpm capability of the new cam, not because it was just changed. People put the new cam in, then spin the **** out of an engine known for spitting rod bearings at high rpm. That's not the cam's fault, that's a problem with the interface between the drivers seat and the steering wheel.

 

That's what I was thinking. I plan on keeping the revs under 6400, so assuming good oil pressure, and compression, maybe just install new cam bearings and that's it? Can I install say ARP rod bolts without taking apart the rods and bearings, or should I just leave it alone as long as I'm shifting say 6300?

Again, this is not my daily driver, only a weekend, and fun car so it's not as bad if the motor goes out because I can still get to work the next day. However I don't want to have to install an engine twice in a few months either.

 

If you're gonna start playing with rod bolts and what not, tear it down and do the whole thing.

 

I'll just leave the rotating assmbly alone unless it needs it then.

 

I wouldnt worry about bearings if the motor is near or under 100k, assuming it passes all of the checks you mentioned above. Get a cam that runs out around 6000 to 6200 rpm's and then you dont have to go past 63 or 64. Even those rpm's can chew up an opti.